Equipment for engaging a safety braking device for a lift cage
A tripping device for engaging an elevator lift cage safety brake has actuating levers arranged at a rotary axle for engaging safety brake wedges of the safety braking device. Each actuating lever has a longitudinal slot matched to the diameter of the rotary axle, wherein the actuating lever is freely movable in the direction of the rotary axle and in the direction of the length of the actuating lever. A torsion spring fixes the actuating lever about the rotary axle. One spring end presses the actuating lever downwardly, wherein the movement of the actuating lever is limited by a lower abutment. The other spring end is detachably connected to a support. An upper abutment limits the movement of the actuating lever upwardly. The lower abutment and the upper abutment are each held at a respective end of a T-shaped shackle, wherein the shackle is fixedly connected to the rotary axle. The freely movable actuating levers facilitate access to the safety brake wedges of the safety braking device and prevent erroneous tripping.
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The invention relates to a device for engaging a safety braking device for a lift cage, and particularly to a tripping device for incorporation in an elevator system having a speed limiter monitoring the speed of the lift cage connected by means of a support cable with a counterweight, wherein the movement of the lift cage or the counterweight is transmitted by means of a limiter cable to the speed limiter, which initiates stopping of the lift installation in the case of excess speed. The tripping device engages the safety braking device and is actuable by means of the limiter cable.
BACKGROUND OF THE INVENTIONA safety braking device which is arranged at a lift cage and by means of which the lift cage can be arrested in the case of excess speed has become known from U.S. Pat. No. 5,782,319. A speed limiter monitors the speed of the lift cage, wherein the lift cage drives a limiter cable guided over the speed limiter. In the case of excess speed of the lift cage, the speed limiter blocks the limiter cable. The blocked limiter cable trips the safety braking device by means of a lever mechanism, whereby safety brake wedges are pressed by means of a spring force against the guide rail. The thus-arising frictional force arrests the lift cage. The safety brake wedges are moved upwardly, when tripped, by means of actuating levers arranged on an axle of the lever mechanism, wherein the safety brake wedges come into contact with the guide rail and are further moved in the housing of the safety braking device by the friction force between safety brake wedge and guide rail.
A disadvantage of the known equipment resides in the fact that stopping of the lift cage can also take place when no need exists. Moreover, the actuating levers are obstructive during demounting of the safety brake wedges.
BRIEF DESCRIPTION OF THE INVENTIONThe invention, avoids disadvantages of known equipment and provides a device that stops the lift cage only in the case of emergency and which is simple to maintain.
The invention is a tripping device that comprises a rotary axle which is associated with safety braking device for the lift cage upon which freely movable actuating levers are mounted. The actuating levers are arranged and constructed to actuate safety brake wedges of the associated safety braking device upon rotation of the rotary axle. The actuating lever may have means to allow the lever to be freely movable both about the rotary axle and in a direction of a length of the actuating lever. Bias means, such as a torsion spring, may be arranged at the rotary axle for fixing the actuating lever.
The tripping device may also include lower and upper stops or abutments for limiting movement of the actuating lever. The abutments may be mounted to the rotary axle. At least one safety switch for monitoring the position of the actuating lever may also be provided. A contact plate can be used to transmit movement of the actuating lever to actuate the safety switch.
The advantages achieved by the invention are essentially to be seen in the fact that the safety braking device is not unnecessarily tripped by the inertia of the limiter cable. This is of benefit, as release of the lift cage from an arrested state requires considerable effort. In addition, the wedges of the safety braking device can damage the guide rails. While unwanted actuation is minimized, stopping of the lift cage in the case of emergency is still ensured. In addition, the actuating levers arranged at the axle to be freely movable permit a simple demounting of the safety brake wedges. Moreover, the freely movable actuating levers automatically adapt to different widths of the guide limb of the guide rail. The mechanical decoupling of the actuating levers from the axle (freely movable actuating levers) is of significance particularly for high speeds of the lift cage. Faulty trippings of the safety braking device would have serious mechanical consequences for the lift cage and the guide rails.
The present invention is explained in more detail in the following detailed description with the accompanying figures, in which:
A lift cage which is movable in a lift shaft 1.1 and is connected with a counterweight by means of a support cable guided over a drive pulley is denoted by 1 in
The lift cage 1 is carried by a support frame 1.4 with a lower yoke 1.6 and an upper yoke 1.5, wherein the support cable guided over the drive pulley (not illustrated) is connected at one end to the upper yoke 1.5 and at the other end to the counterweight (not illustrated). At the lower yoke 1.6 a respective safety braking device 9 is arranged for each guide rail 1.3 to stop the lift cage 1 in the case of emergency. The lift cage 1 drives, by means of the limiter cable 6, the cable pulley of the speed limiter, which in the case of a specific excess speed of the lift cage 1 in the downward direction trips the cable brake and blocks. The cable brake and the block speed limiter also block the limiter cable 6 guided over the deflecting roller arranged in the shaft pit, but the lift cage 1 moves further downwardly, causing the blocked limiter cable 6 connected with the tripping mechanism 8 to engage the safety braking device 9.
The tripping mechanism 8 connected with the limiter cable 6 consists of a first rotary axle 8.1 with tripping lever 8.11 connected to the limiter cable, having actuating levers 8.2 engaging the safety brake 9. The rotary axle 8.1 of the actuating lever 8.2 for the opposite safety braking device 9 is actuated by means of a connecting rod 8.3 between the two rotary axles 8.1. When the limiter cable 6 is blocked the rotary axles 8.1 rotate in a clockwise sense as seen from the cage door 1.2. The free ends of actuating levers 8.2 are raised, which in turn move safety brake wedges 9.1 of the safety braking devices 9 upwardly, wherein the safety brake wedges 9.1 come into contact with the guide rail 1.3 and are further moved by the friction force between safety brake wedges and guide rails in the housing of the safety braking device 9. On standstill of the lift cage 1, the safety brake wedges 9.1 are acted on by spring forces of the spring packet 9.2 of the safety braking device 9.
On the limiter cable side a box 8.41 mounted by a bracket 8.42 is arranged at the support of the limiter cable side support 8.4 and accommodates the tripping levers 8.11, the end of the rotary axle 8.1, the end of the connecting rod 8.3 and a detent spring 8.411. The detent spring 8.411 fixes a bolt 8.111 of the tripping lever 8.11 by a specific force which prevents erroneous tripping of the safety braking device 9. When the spring force is exceeded the bolt 8.111 leaves the detent spring 8.411, wherein the safety braking device 9 is engaged by means of the tripping lever 8.11, the rotary axle 8.1 and the actuating lever 8.2.
Claims
1. A tripping device for engaging at least one elevator lift cage safety braking device upon actuation by a limiter cable, the elevator having a speed limiter monitoring a speed of the lift cage connected by means of a support cable with a counterweight, wherein movement of the lift cage or the counterweight is transmitted by means of the limiter cable to the speed limiter which initiates stopping of the lift cage in the case of excess speed, the tripping device comprising a rotary axle associated with each safety braking device and a plurality of actuating levers mounted in a freely movable manner with respect to the rotary axle upon the rotary axle and coupled thereto actuate safety brake wedges of the safety braking device upon rotation of the rotary axle.
2. The tripping device according to claim 1, wherein′each of the actuating levers have a longitudinal slot matched to a diameter of the rotary axle, whereby the actuating levers are freely movable about the rotary axle and in a direction of a length of the actuating levers.
3. The tripping device according to claim 1 or 2, further comprising a torsion spring arranged at the rotary axle for fixing the actuating levers.
4. The tripping device according to claim 3, wherein the torsion spring has a first spring end is detachably affixed to one of the actuating levers and a second spring end detachably affixed to a support for the rotary axle.
5. The tripping device according to claim 3, further comprising a lower abutment for limiting downward movement of the actuating levers, wherein the lower abutment has ends held by a respective shackle which is fixedly connected with the rotary axle.
6. The tripping device according to claim 5, further comprising an upper abutment for limiting upward movement of the actuating levers, wherein the upper abutment has ends held by the respective shackle fixedly connected with the rotary axle.
7. The tripping device according to claim 1 or 2, further comprising a lower abutment for limiting downward movement of the actuating levers, wherein the lower abutment has ends held by a respective shackle which is fixedly connected with the rotary axle.
8. The tripping device according to claim 7, further comprising an upper abutment for limiting upward movement of the actuating levers, wherein the upper abutment has ends held by the respective shackle fixedly connected with the rotary axle.
9. The tripping device according to claim 7, further comprising at least one safety switch for monitoring the position of the actuating′levers arranged at a support.
10. The tripping device according to claim 9, further comprising a contact plate located to transmit movement of an the actuating′levers to actuate the safety switch.
11. The tripping device according to claim 1 or 2, further comprising at least one safety switch for monitoring the position of the actuating levers arranged at a support.
12. The tripping device according to claim 11, further comprising a contact plate located to transmit movement of the actuating levers to actuate the safety switch.
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- Patent Abstracts of Japan, pub. No. 09240952, Sep. 16, 1997, “Safety Device of Elevator”, Toshiba Corp.
- Patent Abstracts of Japan, pub. No. 2000219450, Aug. 8, 2000, “Elevator Device”, Toshiba Elevator Co Ltd.
Type: Grant
Filed: May 1, 2003
Date of Patent: Oct 31, 2006
Patent Publication Number: 20030226718
Assignee: Inventio AG (Hergiswil)
Inventors: Julien Maury (Lucerne), Stefan Hugel (Adligenswil), Peter Aeschlimann (Sursee)
Primary Examiner: Kathy Matecki
Assistant Examiner: Michael Lowe
Attorney: Schweitzer Cornman Gross & Bondell LLP
Application Number: 10/427,855
International Classification: B66B 5/04 (20060101);